1. Field
The present disclosure relates to a superconducting cable terminal connection device, and more particularly, to a superconducting cable terminal connection device in which a connection portion of a vertical conductor and a horizontal conductor has a mechanically stable support structure.
2. Description of the Related Art
A superconducting cable terminal connection device is a device that connects a superconducting cable and a conducting cable to each other at a terminal point of a superconducting cable system. That is, the superconducting cable terminal connection device is a connection device for connecting the superconducting cable that transmits power at a very low temperature to an overhead power transmission line that is at room temperature or to power equipment such as a breaker.
The superconducting cable terminal connection device has a structure in which an electric field relaxation shield is disposed inside double metal insulation housings, and the superconducting cable and the conducting cable are connected inside the electric field relaxation shield. Specifically, in the structure, a horizontal conductor extending from the superconducting cable is introduced to the inside of the electric field relaxation shield, and a vertical conductor extending from a bus bar of the overhead power transmission line, the power equipment, or the like is introduced so as to connect the horizontal conductor and the vertical conductor to each other.
In addition, since the inner insulation housing (coolant tank) is filled with a coolant (for example, cryogenic liquid nitrogen), the electric field relaxation shield is maintained in a state immersed into the coolant. The coolant is also filled in the electric field relaxation shield, and the inner insulation housing is covered with the outer insulation housing (a vacuum container) that maintains a vacuum insulation gap.
The superconducting cable system uses liquid nitrogen as main insulating material and is driven at a temperature of 65K to 77K. Therefore, heat shrinkage occurs in the superconducting cable due to cryogenic cooling and thus mechanical stress is exerted thereon.
In order to cope with the heat shrinkage, there is a demand for a structure capable of allowing heat shrinkage in the terminal connection device of the superconducting system.
With the demand for the structure, various methods have been considered. However, in the existing methods, even though heat expansion and contraction in the horizontal direction are allowed, it is difficult to implement a structure combined with a structural member that supports the weight of the horizontal conductor. Therefore, the structure becomes useless or becomes structurally complex.
In addition, the existing methods need an additional structure for spacing the electric field relaxation shield to be fixed at the center portion of the inside of the insulation housing.
In addition, in the existing methods, a structural member that supports the electric field relaxation shield and a structural member that supports the horizontal conductor are separate members and supported separately, so that the structure becomes more complex and it is very difficult to manufacture the structure.